A multiplayer online game is a multiplayer video game which can be played via a game server over the internet, with other players around the world. A massively multiplayer online game (also called MMO and MMOG) is a multiplayer video game which is capable of supporting large numbers of players simultaneously. By necessity, they are played on the Internet. Many games have at least one persistent world; however others just have large numbers of players competing at once in one form or another without any lasting effect to the world at all. Multiplayer online game games differ from MMOGs in that they do not create a persistent world, but create a playing arena for the purpose of a single game or round. In other words, they rely on a game listen server used only for that round, and there can be numerous servers all around the world. MMOGs on the other hand, rely on dedicated servers, as these games must be running continuously.
Games that support and promote cooperative play are rapidly increasing in popularity. The load on bandwidth, on the server side, to support so many players can be significant. This load is increasing due to the rise in popularity of multiplayer online games and MMOGs.